Is combofix safe to use

Hello everyone i have mcafee antivirus in my network but it is of no use, it doesnot catch much viruses even though it catches threats it doesnot restore the default registry settings,
i use tools two tools like combofix and winsocfix and atlast i use SubInACL.exe(My favourite one which is Microsofts it restore all default registry settings) and my work gets done,but in some situations it doesn't , Are there any free tools like these which can help me more , because my network is not connected to internet. please guide me and also is combofix safe to use but it is a very good tool
byee